/*
 * Copyright 2002-2009 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.core.type.classreading;

import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;

import org.springframework.asm.AnnotationVisitor;
import org.springframework.asm.MethodVisitor;
import org.springframework.asm.Type;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.MethodMetadata;

/**
 * ASM class visitor which looks for the class name and implemented types as
 * well as for the annotations defined on the class, exposing them through
 * the {@link org.springframework.core.type.AnnotationMetadata} interface.
 *
 * @author Juergen Hoeller
 * @author Mark Fisher
 * @since 2.5
 */
final class AnnotationMetadataReadingVisitor extends ClassMetadataReadingVisitor implements AnnotationMetadata {

    private final ClassLoader classLoader;

    private final Set<String> annotationSet = new LinkedHashSet<String>();

    private final Map<String, Set<String>> metaAnnotationMap = new LinkedHashMap<String, Set<String>>();

    private final Map<String, Map<String, Object>> attributeMap = new LinkedHashMap<String, Map<String, Object>>();

    private final Set<MethodMetadata> methodMetadataSet = new LinkedHashSet<MethodMetadata>();


    public AnnotationMetadataReadingVisitor(ClassLoader classLoader) {
        this.classLoader = classLoader;
    }


    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        MethodMetadataReadingVisitor mm = new MethodMetadataReadingVisitor(name, access, this.classLoader);
        this.methodMetadataSet.add(mm);
        return mm;
    }

    @Override
    public AnnotationVisitor visitAnnotation(final String desc, boolean visible) {
        String className = Type.getType(desc).getClassName();
        this.annotationSet.add(className);
        return new AnnotationAttributesReadingVisitor(className, this.attributeMap, this.metaAnnotationMap, this.classLoader);
    }


    public Set<String> getAnnotationTypes() {
        return this.annotationSet;
    }

    public Set<String> getMetaAnnotationTypes(String annotationType) {
        return this.metaAnnotationMap.get(annotationType);
    }

    public boolean hasAnnotation(String annotationType) {
        return this.annotationSet.contains(annotationType);
    }

    public boolean hasMetaAnnotation(String metaAnnotationType) {
        Collection<Set<String>> allMetaTypes = this.metaAnnotationMap.values();
        for (Set<String> metaTypes : allMetaTypes) {
            if (metaTypes.contains(metaAnnotationType)) {
                return true;
            }
        }
        return false;
    }

    public boolean isAnnotated(String annotationType) {
        return this.attributeMap.containsKey(annotationType);
    }

    public Map<String, Object> getAnnotationAttributes(String annotationType) {
        return getAnnotationAttributes(annotationType, false);
    }

    public Map<String, Object> getAnnotationAttributes(String annotationType, boolean classValuesAsString) {
        Map<String, Object> raw = this.attributeMap.get(annotationType);
        if (raw == null) {
            return null;
        }
        Map<String, Object> result = new LinkedHashMap<String, Object>(raw.size());
        for (Map.Entry<String, Object> entry : raw.entrySet()) {
            try {
                Object value = entry.getValue();
                if (value instanceof Type) {
                    value = (classValuesAsString ? ((Type) value).getClassName() :
                            this.classLoader.loadClass(((Type) value).getClassName()));
                }
                else if (value instanceof Type[]) {
                    Type[] array = (Type[]) value;
                    Object[] convArray = (classValuesAsString ? new String[array.length] : new Class[array.length]);
                    for (int i = 0; i < array.length; i++) {
                        convArray[i] = (classValuesAsString ? array[i].getClassName() :
                                this.classLoader.loadClass(array[i].getClassName()));
                    }
                    value = convArray;
                }
                result.put(entry.getKey(), value);
            }
            catch (Exception ex) {
                // Class not found - can't resolve class reference in annotation attribute.
            }
        }
        return result;
    }

    public boolean hasAnnotatedMethods(String annotationType) {
        for (MethodMetadata method : this.methodMetadataSet) {
            if (method.isAnnotated(annotationType)) {
                return true;
            }
        }
        return false;
    }

    public Set<MethodMetadata> getAnnotatedMethods(String annotationType) {
        Set<MethodMetadata> annotatedMethods = new LinkedHashSet<MethodMetadata>();
        for (MethodMetadata method : this.methodMetadataSet) {
            if (method.isAnnotated(annotationType)) {
                annotatedMethods.add(method);
            }
        }
        return annotatedMethods;
    }

}
